Ir sensor for electronic thermometer

ABSTRACT

An electronic thermometer includes a probe adapted to be heated by a subject for use in measuring a temperature of the subject. At least one temperature sensor detects a temperature of the probe. An IR emitter emits an infrared signal from the probe. And an IR detector detects the infrared signal emitted by the IR emitter. The detection of the IR signal by the IR detector indicates that the probe is received in a probe cover.

BACKGROUND

The present invention generally relates to thermometers, and moreparticularly to a thermometer having an IR probe sensor.

Medical thermometers are typically employed to measure a subject's bodytemperature to facilitate the prevention, diagnosis, and treatment ofdiseases, body ailments, etc., for humans and other animals. An accuratereading of a subject's body temperature is required for effective useand should be taken from the internal or core temperature of a subject'sbody. Several thermometer devices are known for measuring a subject'sbody temperature, such as, for example, electronic thermometers,including tympanic thermometers.

Tympanic thermometers have a sensing probe that is inserted into asubject's cavity (e.g., ear) for measuring the subject's bodytemperature. Before inserting the sensing probe into the subject'scavity, a probe cover is preferably mounted onto the sensing probe toprovide a sanitary barrier between the sensing probe and the subject.The probe cover is typically discarded after the subject's bodytemperature has been obtained.

In the case of a tympanic thermometer, the sensing probe includes a heatsensor such as a thermopile for sensing infrared emission from thetympanic membrane, or eardrum. During use, the thermopile is generallylocated inside the ear canal. The thermopile utilizes a waveguide ofradiant heat to transfer heat energy from the eardrum to the sensor.

Often times during use, the thermometer probe is inadvertently placedinto a subject's cavity without a probe cover. This exposes thethermometer to cross contamination, which compromises the ability of thethermometer to generate accurate reading and necessitates cleaning theprobe. A conventional thermometer cannot detect the placement of theprobe in the subject's cavity. Therefore, a need exists for athermometer that can better promote proper usage of the thermometer,including the placement of the probe.

SUMMARY

In one aspect, an electronic thermometer generally comprises a probeadapted to be heated by a subject for use in measuring a temperature ofthe subject. At least one temperature sensor detects a temperature ofthe probe. An IR emitter emits an infrared signal from the probe. And anIR detector detects the infrared signal emitted by the IR emitter. Thedetection of the IR signal by the IR detector indicates that the probeis received in a probe cover.

In another aspect, a method of determining a temperature of a subjectwith an electronic thermometer generally comprises emitting an IR signalout of a probe with an IR emitter. Detecting the IR signal emitted bythe IR emitter with an IR detector. The detection of the IR signal bythe IR detector indicating that the probe is received in a probe cover.And detecting a temperature of the probe when inserted into the subjectby using a temperature sensor to determine the temperature of thesubject.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a tympanic thermometer, in accordancewith the principles of the present disclosure, mounted on a holder;

FIG. 2 is a perspective view of the tympanic thermometer shown in FIG. 1with a probe cover disposed on a distal end of the thermometer;

FIG. 3 is a perspective view of the probe cover shown in FIG. 2;

FIG. 4 is an exploded perspective view of the distal end of the tympanicthermometer shown in FIG. 2;

FIG. 5 is a cross-sectional and fragmentary view of the probe covermounted on the distal end of the tympanic thermometer taken through line5-5 of FIG. 6;

FIG. 6 is an end view of the distal end of the tympanic thermometer;

FIG. 7 is a cross-sectional and fragmentary view taken through line 7-7of FIG. 6 showing the probe cover mounted on the distal end of thetympanic thermometer;

FIG. 8 is a block diagram of an IR system of the tympanic thermometer;

FIG. 9 is an enlarged perspective view of the probe cover mounted on thedistal end of the tympanic thermometer with portions broken away showinginternal detail;

FIG. 10 is an end view of a second embodiment of a distal end of a probeof the tympanic thermometer; and

FIG. 11 is a flow chart showing a control sequence performed by aprocessor of the tympanic thermometer.

Other objects and features will be in part apparent and in part pointedout hereinafter.

DETAILED DESCRIPTION

The exemplary embodiments of the tympanic thermometer and methods of usedisclosed are discussed in terms of medical thermometers for measuringbody temperature and, more particularly, in terms of a tympanicthermometer that includes a temperature sensor for measuring bodytemperature when the thermometer is inserted into an ear of a subject.However, the disclosed elements can be used with other types ofelectronic thermometers (ex., oral and rectal thermometer) withoutdeparting from the scope of the present invention.

In the discussion that follows, the term “proximal” will refer to theportion of a structure that is closer to a practitioner, while the term“distal” will refer to the portion that is farther from thepractitioner. FIG. 2 illustrates “proximal” and “distal” for thestructure, which is the fully assembled and usable tympanic thermometer.As-used herein, the term “subject” refers to a human patient or otheranimal having its body temperature measured. According to the presentdisclosure, the term “practitioner” refers to a doctor, nurse, parent orother care provider utilizing a tympanic thermometer to measure asubject's body temperature, and may include support personnel.

Reference will now be made in detail to exemplary embodiments of thepresent disclosure, which are illustrated in the accompanying Figures.Turning now to the Figures and initially to FIGS. 1 and 2, there isillustrated a tympanic thermometer, generally indicated at 20, inaccordance with the principles of the present disclosure. It iscontemplated that the tympanic thermometer 20 includes the necessaryelectronics and/or processing components to perform temperaturemeasurement via the tympanic membrane, as is known to one skilled in theart. It is further envisioned that tympanic thermometer 20 may include awaveguide to facilitate sensing of the tympanic membrane heat energy.However, in the illustrated embodiments, the waveguide is beneficiallyomitted. The tympanic thermometer 20 is releasably mounted in a holder40 for storage in contemplation for use. The tympanic thermometer 20 andholder 40 may be fabricated from semi-rigid, rigid plastic and/or metalmaterials suitable for temperature measurement and related use. It isenvisioned that the holder 40 may include the electronics necessary tofacilitate powering the tympanic thermometer 20, including, for example,battery charging capability, etc. The thermometer 20 is operable in asleep mode wherein the thermometer 20 conserves energy and is notcapable of performing a temperature measurement and an awake modewherein the thermometer is operating at full power and is capable ofperforming a temperature measurement in certain conditions as will bedescribed in greater detail below.

Referring to FIGS. 2-5, tympanic thermometer 20 includes a cylindricalheat sensing probe, generally indicated at 22. The heat sensing probe 22extends from a distal end 24 of tympanic thermometer 20 and defines alongitudinal axis X. The heat sensing probe 22 may have variousgeometric cross-sectional configurations, such as, for example,rectangular, elliptical, etc.

A probe cover 32 may be disposed over the heat sensing probe 22. Theprobe cover 32 has a distal end 54 that is substantially enclosed by afilm 56. The film is substantially transparent to infrared radiation andconfigured to facilitate sensing of infrared emissions by heat sensingprobe 22. The film 56 is advantageously impervious to ear wax, moistureand bacteria to prevent disease propagation. One skilled in the art,however, will realize that other materials and fabrication methodssuitable for assembly and manufacture are also within the scope of thepresent invention.

Referring to FIGS. 4 and 5, the heat sensing probe 22 includes a nozzle,generally indicated at 100, mounted on a base 106. The nozzle 100includes a base 110 and an elongated nose portion 112 projectingdistally from the base. By way of non-limiting example, nozzle 100 maybe fabricated from metal or other material which aides in the rapidexchange or transfer of heat. The nozzle 100 is formed of two parts (thebase 110 and the nose portion 112) in the illustrated embodiment. Itwill be understood that a nozzle can be formed as one piece or more thantwo pieces without departing from the scope of the present invention. Inparticular, it is envisioned that the elongated nose section 112 can beformed of two or more pieces.

The heat sensing probe 22 also includes a sensor can, generallyindicated at 102, attached to temperature sensing electronics mounted ona distal end of a sensor housing 104 (or “retainer”) received within thenozzle 100. The can 102 includes a sensor base 126 and a generallyinverted cup-shaped tip 116 mounted on the base. A temperature sensor122 (e.g., a thermopile), an infrared filter or window 120 andthermistor 124 are housed within can 102. The sensor housing 104 ismounted on the base 106 of probe 22 such that it extends generallycoaxially within nozzle 100. By way of non-limiting example, the sensorhousing 104 is fabricated from materials that provide for less thermotransmission (i.e., more insulated) than the nozzle 100, for example,plastic or other similar matter. So the material of the sensor housing104 has a low thermal conductivity as compared to the thermalconductivity of the nozzle 100 and the base 126 of the can 102. Theprobe may also include a probe cover film 119 (FIG. 8).

The probe cover 32 is received on the nozzle 100 such that a distalportion of the cover is in thermal contact with the nose 112 of thenozzle. Probe cover 32 may be shaped, for example, frustoconically, orshaped in a tapered manner as to allow for easier insertion into the earof the subject and attachment and detachment from the heat sensing probe22. The probe cover 32, which is disposable, may be fabricated frommaterials suitable for measuring body temperature via the tympanicmembrane with a tympanic thermometer measuring apparatus. Thesematerials may include, for example, plastic materials, such as, forexample, polypropylene, polyethylene, etc., depending on the particulartemperature measurement application and/or preference of a practitioner.

In operation, infrared energy IR (FIG. 5) from the subject's tympanicmembrane, for example, passes through the film 56 of probe cover 32 andenters can 102 through the window 120 of probe 22. This infrared energymay heat the can 102 and create a temperature gradient across the tip116 from its distal end to its proximal end contacting the base 126.That is, the distal end can be much warmer than the proximal end. Heatfrom, for example, the ear of the subject is transferred from probecover 32 to nozzle 100 to the base 126 of the can 102 via a path of heatflux (not shown). The path of heat flux heats the can 102 in order toreduce the temperature gradient across tip 116, thereby enabling afaster and more accurate temperature reading. An internal ridge 121engages a distal side of a peripheral edge margin 114 of the base 126 toprovide a heat conducting path from the nozzle 100 to the base 126defining the path of heat flux. It is contemplated herein that nozzle100 may be both in physical contact with the peripheral edge margin 114or in a close proximate relationship with peripheral edge margin 114 ofcan 102. In either case, there should be such thermal contact as toenable heat transfer from the internal ridge 121 of the nozzle 100 tothe peripheral edge margin 114 of the base 126.

Referring to FIGS. 5-8, an IR signal emitter 130 and an IR signaldetector 132 are disposed in a wall of the nozzle 100 at a proximal endof the nozzle. The IR signal emitter 130 is configured to emit aninfrared signal and the IR signal detector 132 is configured to detectthe infrared signal emitted by the IR signal emitter when the probe 22is received in the probe cover 32. In one embodiment, the IR emitteremits an infrared signal within about a 940 nm wavelength range and theIR detector 132 generates a voltage level that is proportional to thestrength of the infrared signal detected by the IR detector. A constantcurrent source 131 provides electric current to the IR signal emitter130. And, in one embodiment, a signal conditioner 133 conditions thevoltage signal produced by the IR signal detector 132 to condition thesignal into a suitable form to be processed by a controller (not shown)of the thermometer 20. The constant current source 131, IR signalemitter 130, IR signal detector, and signal conditioner 133 comprise anIR system.

An emitter fiber 134 extends within the wall of the nozzle 100 along alength of the nozzle from the IR emitter 130 at the proximal end of thenozzle to a distal end of the nozzle. In one embodiment, the emitterfiber 134 comprises fiber optic strands for conducting an infraredsignal. The emitter fiber 134 terminates at an emitter opening 136 inthe distal end of the nozzle 100 so that the emitted infrared signal isconducted out of the distal end of the nozzle.

A detector fiber 138 extends within the wall of the nozzle 100 along thelength of the nozzle from the IR detector 132 at the proximal end of thenozzle to the distal end of the nozzle. The detector fiber 138 alsocomprises, for example, fiber optic strands for conducting an infraredsignal. The detector fiber 138 terminates at a detector opening 140 inthe distal end of the nozzle 100 so that the emitted infrared signalfrom the IR emitter 130 can be conducted to the IR detector 132 when theprobe 22 is received in the probe cover 32. In particular, the film 56of the probe cover 32 reflects the infrared signal emitted by the IRemitter 130 into the detector opening 140 and to the detector fiber 138so that the infrared signal can be conducted to the IR detector 132.

As shown in FIG. 9, the infrared signal IRS is reflected multiple timesbetween an inner surface of the film 56 and distal edge of the nozzle100 until the signal reaches the detector opening 140. Once the signalis directed to the detector opening 140, the detector fiber 138 conductsthe signal to the IR detector 132. The detection of the infrared signalby the IR detector 132 indicates that the probe 22 is received in theprobe cover 32.

In the illustrated embodiment, the emitter opening 136 and detectoropening 140 are spaced about 90 degrees from each other to ensure thatthe infrared signal reaches the IR detector 132 without having to travelan extended distance. However, the openings 136, 140 can be spaced atother distances and angles from each other without departing from thescope of the invention. For instance, FIG. 10 shows a second embodimentof a probe 222 of the present invention having several options forpossible emitter and detector openings. Also, the IR signal emitter 130and IR signal detector 132 can be disposed at the distal end of theprobe 22 near the emitter opening 136 and detector opening 140,respectively. In this embodiment, the emitter fiber 134 and detectorfiber 138 may be omitted.

The temperature sensor 122, IR signal emitter 130, IR signal detector132, constant current source 131, and signal conditioner 133 areoperatively connected to a microprocessor system including a processor(not shown) of the controller. The processor is programmed to performthe temperature measurements for determining the temperature of thesubject through the connection between the processor and the temperaturesensor 122. The processor may also control the IR system for detectingthe placement of the probe 22 as will be explained in greater detailbelow.

Referring to FIG. 11, the processor may control the IR system so thatwhen the thermometer 20 is in the sleep mode, and when the thermometeris in the awake mode, but the probe 22 is not received in the probecover 32, the processor will deactivate the IR system. In these twoconditions, the processor may also be programmed to prevent power frombeing supplied to the temperature sensor 122. Thus, the thermometer 20would not be capable of performing a temperature measurement. When theprobe 22 is fully inserted into the probe cover 32, the probe coverengages a switch (not shown) on the probe and switches the thermometer20 to the awake mode so that the processor may activate the IR system.Although the microprocessor of the thermometer is described ascontrolling both the temperature measurements and the IR system, aseparate processor from the thermometer microprocessor may control theIR system.

When the IR system is activated, the processor can be programmed toidentify a first condition wherein the infrared signal detected by theIR detector 132 indicates that the probe 22 is received in the probecover 32 but not inserted into the subject, and a second conditionwherein the infrared signal detected by the IR detector indicates thatthe probe is received in the probe cover and inserted into the subject.The processor can be programmed to provide an indication, such as aread-out on a display 30 of the thermometer 20, notifying thepractitioner which condition is being detected by the IR system.However, the indications can be provided in other ways such as audibleindications without departing from the scope of the invention.

By way of example, when the processor identifies the first condition,the IR detector produces a voltage based on the received infraredenergy; this voltage will be the reference voltage. When the processoridentifies the second condition, the IR detector detects a voltage levelshift from the reference voltage established during the first condition.The voltage ranges corresponding to the first and second conditions canhave other values without departing from the scope of the invention.

The processor can also be programmed to activate the temperature sensor122 to measure the temperature of the subject only after the processoridentifies the second condition wherein the probe 22 is received in theprobe cover 32 and inserted into the subject. This improves the accuracyof the thermometer 20 because power is not supplied to the temperaturesensor 122 until the probe 22 is properly inserted into the subject.Also, external effects on the temperature sensor 122 are minimizedmaking the temperature readings produced by the temperature sensor moreaccurate. Once the thermometer 20 acquires the subject's temperature,the processor may deactivate the IR system to conserve battery life andprevent the reuse of the probe cover.

Having described the invention in detail, it will be apparent thatmodifications and variations are possible without departing from thescope of the invention defined in the appended claims.

When introducing elements of the present invention or the preferredembodiments(s) thereof, the articles “a”, “an”, “the” and “said” areintended to mean that there are one or more of the elements. The terms“comprising”, “including” and “having” are intended to be inclusive andmean that there may be additional elements other than the listedelements.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

As various changes could be made in the above constructions and methodswithout departing from the scope of the invention, it is intended thatall matter contained in the above description and shown in theaccompanying drawings shall be interpreted as illustrative and not in alimiting sense.

1. An electronic thermometer comprising: a probe adapted to be heated by a subject for use in measuring a temperature of the subject; at least one temperature sensor for detecting a temperature of the probe; an IR emitter for emitting an infrared signal from the probe; and an IR detector for detecting the infrared signal emitted by the IR emitter, the detection of the IR signal by the IR detector indicating that the probe is received in a probe cover, the infrared signal being reflected by a film of the probe cover to the IR detector. 2-27. (canceled)
 28. An electronic thermometer as set forth in claim 1 further comprising a processor operatively connected to the IR emitter and IR detector and programmed to monitor the infrared signal detected by the IR detector to determine a first condition wherein the infrared signal indicates that the probe is received in a probe cover and not inserted into the subject and a second condition wherein the infrared signal indicates that the probe is received in a probe cover and inserted into the subject.
 29. An electronic thermometer as set forth in claim 28 wherein the processor is operatively connected to the at least one temperature sensor and programmed to activate the at least one temperature sensor to measure the temperature of the subject only after the processor identifies the second condition wherein the IR detector detects an infrared signal within a predetermined range indicating that the probe is received in a probe cover and inserted into the subject.
 30. An electronic thermometer as set forth in claim 29 wherein the processor is programmed to temporarily deactivate the at least one temperature sensor and either the IR emitter or the IR detector or both after the temperature of the subject is measured to prevent reuse of the probe cover.
 31. An electronic thermometer as set forth in claim 1 wherein the IR emitter and IR detector are disposed at a proximal end of the probe.
 32. An electronic thermometer as set forth in claim 31 further comprising an emitter fiber and a detector fiber each extending along a length of the probe from the proximal end of the probe to a distal end of the probe, the emitter fiber conducting the infrared signal emitted by the IR emitter to the distal end of the probe, the infrared signal being reflected by the film of the probe cover to the detector fiber which conducts the reflected signal to the IR detector disposed at the proximal end of the probe when the probe is received in the probe cover.
 33. An electronic thermometer as set forth in claim 32 wherein the emitter fiber and detector fiber are both fiber optic strands for conducting the infrared signal.
 34. An electronic thermometer as set forth in claim 1 and wherein the IR emitter and IR detector are disposed at a distal end of the probe.
 35. An electronic thermometer as set forth in claim 1 wherein the infrared signal is reflected multiple times by the film of the probe cover before being detected by the IR signal detector when the probe is received in the probe cover.
 36. An electronic thermometer as set forth in claim 1 further comprising an emitter opening and a detector opening, wherein the probe is generally tubular, the emitter opening being spaced circumferentially about 90 degrees from the detector opening.
 37. An electronic thermometer as set forth in claim 1 wherein the thermometer is a tympanic thermometer.
 38. A method of determining a temperature of a subject with an electronic thermometer, said thermometer having a probe adapted to be heated by a subject and at least one temperature sensor for detecting a temperature of the probe, said method comprising: emitting an IR signal out of the probe; detecting the IR signal after the signal is reflected by a film of a probe cover, the detection of the IR signal indicating that the probe is received in the probe cover; enabling the temperature sensor to detect the temperature of the probe when the probe is received in the probe cover; and detecting a temperature of the probe when inserted into the subject by using the temperature sensor to determine the temperature of the subject.
 39. An electronic thermometer comprising: a probe adapted to be heated by a subject for use in measuring a temperature of the subject; at least one temperature sensor for detecting a temperature of the probe; an IR emitter for emitting an infrared signal from the probe; an IR detector for detecting the infrared signal emitted by the IR emitter, the detection of the IR signal by the IR detector indicating that the probe is received in a probe cover; and a processor operatively connected to the at least one temperature sensor and programmed to activate the at least one temperature sensor to measure the temperature of the subject only after the processor identifies a condition wherein the IR detector detects an infrared signal within a predetermined range indicating that the probe is received in a probe cover and inserted into the subject such that the temperature sensor cannot detect the temperature of the probe if the processor does not identify said condition.
 40. An electronic thermometer as set forth in claim 39 wherein the processor is programmed to temporarily deactivate the at least one temperature sensor and either the IR emitter or the IR detector or both after the temperature of the subject is measured to prevent reuse of the probe cover. 